1. Field of the Invention
The present invention relates to water flow measuring devices, and more particularly, to water flow measuring devices for use with fire-fighting equipment such as fire hydrants or building fire pumps.
2. Background
In the construction of most buildings, UL and/or FM approved fire pumps are incorporated. The pumps provide water pressure for fire sprinklers, hydrants, or a standpipe system where the available source of water pressure is inadequate. Building sprinkler systems designed for extinguishing fires within the building and fire standpipes often carry extremely high water pressures. All approved fire pumps are constructed and factory tested pursuant to the National Fire Protection Association (“NFPA”) regulations. Most state and local fire and building regulatory agencies, as well as insurance underwriters, have adopted the NFPA regulations or code for testing fire pumps.
It is necessary to test the water pressure in the building fire suppression systems periodically to meet fire and safety codes. The NFPA code requires field testing of each new pump and annual testing of existing pumps. Under supervision of local building and fire authorities, the pumps are tested with full water flow to verify that the pump, the supply piping, and the water source meet the design demand of the fire suppression system of the building.
To test a typical system, the sprinkler system or standpipe is usually connected to a hose and a playpipe to allow the free flow of high pressure water through the system and out the playpipe. Typically, temporary hoses are attached to an available connection and the water is released. A playpipe or flow diverter may be connected to the end of the hose to allow flow measurements at the exiting water stream. A measuring device, such as a pitot tube, determines the flow of water exiting the hose/playpipe. During pressure tests, water may be allowed to discharge from these systems for anywhere from a few minutes to half-an-hour or more.
The water discharged from the playpipe typically cannot be directed with any great specificity or accuracy to a particular area, but instead flows primarily outdoors in the immediate vicinity of the building that contains the system under test. The water is often discharged adjacent to the building wall or hydrant. Additionally, when water under high pressure is released to atmospheric pressure, considerable forces are in play on the discharge stream. High-pressure water spraying from the hose releases very strong forces that are difficult to control and tend to cause the hose and playpipe to swing from side to side and whip violently. Typically, the playpipe or flow diverter needs to be restrained during testing. Extreme care must be exercised with regard to where the water is discharged. The high-pressure water from the playpipe may dig holes in streets, driveways, parking lots, and lawns, with results very similar to hydraulic mining. Damage to the ground, surrounding landscaping, and harm to individuals in the path of the water can occur due to a misdirected water stream.
Building sites and crowded city locations rarely afford sufficient spray areas without interrupting traffic for long periods or without potential harm to pedestrians and nearby property. Many new pump installation tests are conducted on dirt pad sites of new building construction. Such sites typically cannot handle the high-pressure sprays and large volume of water runoff for the full duration of the flow test. Thus, the tests are often shorter in length than necessary and cannot provide accurate results because the tester is unable to provide flow for the appropriate time. Other sites may not have the physical space necessary to accommodate the full spray of water under high pressure without damage to surrounding property.
As safety codes and standards have improved over the years, accuracy in testing is of an increasing importance. To perform a flow test properly using current methods the following must take place.                1. Typically, three persons are required. One person is located at the fire pump inside the building performing tests, one person is located at the fire pump's flow test header on the building, and one person is located at the flow point of discharge. The person at the flow test header and the person at the flow point of discharge must communicate with each other to accurately adjust the flow pressure to required levels. When multiple flows are required to meet a certain demand, the task gets much more difficult. When the volume of one flow device is adjusted higher, the other flow devices decrease in volume, thus requiring much more time to set all flow devices to required pressures accurately.        2. The area at the flow point of discharge, the majority of the time, could exceed 30 yards in diameter. Bridge devices are sometimes used to stack flow discharge units where several units can flow at one location. However, in most conditions, more than three discharge flow devices are required thus making it difficult to accurately measure flows. The person at the flow point of discharge will need to walk back in forth from one test point to the other, communicating with the person at the flow test header to open or close valves to increase/decrease flows, back and forth several times to verify all flow points of discharge are reading the required pressures. After verification, the person at the flow point of discharge moves away from the test area allowing the person at the fire pump to perform tests. In some cases, the hose valves at the flow test header, due to heavy vibration, will slowly open creating inaccurate flows at the flow point of discharge. This is common, and the person at the test header must watch the valve handles to make sure this does not happen. Even when watching closely, if the handle moves in the slightest way, the flows are compromised. Having the person at the flow point of discharge not continuously watching the pressure gages because the person has moved from his position, can result in the flow test results not being accurate.        3. Having to move back in forth several times to measure flows at the point of discharge requires excessive time and excessive water usage.        4. The difficulty of providing unrestricted access to the test equipment is that water backsplash is difficult to control. The difficulty increases as the size of the device reduces. An unrestricted access flow diverter must allow the operator access to the measurement and control devices without getting him wet in the process. The device should prevent any backsplash of the fluid in the area where access is required. The person at the flow point of discharge, at 90% of the flow test locations, gets soaking wet from the knees down.        5. Excessive turbulence will greatly affect flow readings. Unfortunately, it is practically impossible to eliminate water turbulence. Fire hoses used are typically 2½-inch size. Any bends, curves, and/or kinks in any fire hose will create water turbulence thus resulting in inaccurate measurements.        
There is a need for a high-pressure water testing apparatus that is easy to control; that dissipates the pressure from the system under test; and that is easy to use.